The present invention relates to a tool ring for securing preferably elongate bodies in a machine, eg for the manufacture of heads on said elongate bodies, said tool ring having an axis of rotation, an outer circumference and a surface extending substantially perpendicular to the axis of rotation; and wherein the tool ring further comprises a number of engagement means arranged for receiving and releasably securing bodies and spaced substantially equally apart at the circumference of the tool ring, said engagement means each comprising two mutually opposed holding jaws, and wherein at least one of the two holding jaws is/are arranged on a movement mechanism which is arranged to enable the holding jaw to be displaced towards and away from, respectively, the opposed holding jaw.
Such tool ring is known ia from Danish patent Nos 143 935 and 163 111. The tool ring is used in these machines for the manufacture of nails, wherein the tool ring is rotatably suspended about the axis of rotation of the tool ring opposite a wire cutter that serves to cut off elongate wire bodies from a storage of metal wire and shift said elongate bodies onwards for receiving and securing on the tool ring. The tool ring is arranged opposite a second tool ring, the circumference of which corresponds to this tool ring, but it is not provided with engagement means. This second tool ring is also rotatably suspended about an axis of rotation which is substantially coaxial with the axis of rotation of the first tool ring, but having an angulation of a few degrees relative to the axis of rotation of the first tool ring, whereby an elongate body arranged between the tool rings is secured there between in that area where the distance between the tool rings is relatively small, and wherein the elongate body is loosened between the tool rings at the substantially opposite side of the tool rings.
In this context, the term xe2x80x98nailxe2x80x99 is used to designate any object having a shaft which is, at its one end, provided with a head.
In the area where the elongate body is secured between the two tool rings, the wire body is so well secured that it is possible to forge or roll a head onto the one end of the wire body, and for this purpose the tool rings are, at each engagement means, provided with a plurality of opposed pairs of holding trays made of an extremely wear resistant material and each having a groove for receiving the elongate body. Here the engagement means in the tool ring serves to engage with the elongate body and to secure and position it in such a manner that with a high degree of certainty the body will be correctly positioned in the groove in the holding trays when the holding trays closes in on the elongate body.
Thus, the known nail machines function by the tool rings being caused to rotate synchronously about their axes of rotation, whereby the individual pairs of holding trays are successively conveyed past the wire cutter that inserts an elongate body between the tool rings, each of said engagement means engaging with and positioning an elongate body between the two tool rings which subsequently, by their rotation, remove the elongate object and lock it between the tool rings, following which a head is rolled onto the one end of the elongate body, and wherein the tool rings subsequently release the elongate body in the form of a nail or the like.
It is a problem with these prior art nail machines to control and synchronise the wire cutter to ensure that the individual elongate bodies are reliably introduced between the holding jaws on each of the engagement means, said holding jaws being arranged in or radially opposite the space between the tool rings. In practice, this means that the speed of rotation of the tool rings is restricted by the need for introducing an elongate body during that period of time when the engagement means are positioned directly opposite the wire cutter, and that the productivity can be increased for a given nail machine only if the number of holding trays with accompanying engagement means is increased. In practice this means that the known tool rings typically contain about 20 to 40 sets of holding trays and accompanying engagement means.
In the light of this, it is the object of the present invention to provide a tool ring that allows a higher degree of freedom when it comes to obtaining a desired productivity for a given nail machine without necessarily entailing that a given number of holding trays with accompanying engagement means are required.
This is obtained by use of a tool ring as described in the introductory part and characterised in that the movement mechanism for displacing at least the one holding jaw is so configured that it displaces the holding jaw completely or partially in a radial or axial direction relative to the axis of rotation of the tool ring. As opposed to the known tool rings, and provided the tool ring is rotated such that the displaceable holding jaw of each pair of holding jaws is located opposite the opposed holding jaw in the direction of rotation of the tool ring, this enables the elongate body to be advanced to the tool ring to occupy a position in which the elongate body can be seized by the holding jaws in the engagement device before said engagement means becomes positioned opposite the wire cutter. This means that, at a given speed of rotation for the tool ring, more time is available for introducing the elongate body whereby the above-described limitation imposed on the productivity obtainable with a given tool ring having a given number of holding trays and accompanying engagement means is eliminated or at least considerably reduced.
According to a particularly preferred embodiment of the invention it is obtained that undesired variations in the positioning of the individual elongate bodies due to play, if any, in the movement mechanisms of the engagement means, are eliminated or at least considerably reduced by one of the holding jaws in the engagement means being immovably secured on the tool ring, and by the tool ring being configured for rotation in such direction that the immovable holding jaw in each engagement means is situated opposite the immovably secured holding jaw.
Advantageously the engagement means is arranged for receiving and securing the elongate bodies in such a manner that the elongate bodies extend completely or partially opposite that surface of the tool ring which is arranged substantially perpendicular to the axis of rotation, and substantially radially inwards towards the axis of rotation of the tool ring and wherein the movement mechanism is so configured that it displaces the movable holding jaw completely or partially in a direction which is axial in relation to the axis of rotation of the tool ring. Hereby it is accomplished that the individual elongate bodies can be introduced radially between the tool ring according to the present invention and a second tool ring arranged oppositely as described above with reference to the prior art nail machines.
According to a particularly simple and reliable embodiment, each of the movement mechanisms in the tool ring is so configured as to comprise a shaft which is rotatably arranged in the tool ring; and the movable holding jaw is arranged on a lever which is secured to the shaft of the movement mechanism and extends radially therefrom; and a cam follower is also mounted on the rotatable shaft. Hereby a movement mechanism is established that comprises only a rotatable bedding of the movement mechanism whereby a mechanism is provided which is relatively maintenance-free.
The cam follower is advantageously spring actuated such as to move the movable jaw against the opposed jaw. Thereby no adjustments are necessary in order to produce nails from wires having different diameters.
According to a preferred embodiment, the tool ring is so configured that the rotatable shaft of the movement mechanism is arranged such that its axis of rotation points substantially radially inwards towards the axis of rotation of the tool ring. Hereby a movement pattern is obtained for the movable holding jaw that ensures that, in its position near the opposed holding jaw, the movable holding jaw moves substantially in a direction perpendicular to the opposed holding jaw.
According to a particularly preferred embodiment, the tool ring has such configuration that the immovably secured holding jaw has a substantially planar holding surface that faces in the direction of rotation of the tool ring; and that the movable holding jaw has a substantially planar holding surface that faces essentially towards the immovably secured holding surface. Hereby adequate attachment of the elongate bodies is obtained which ensures that the bodies are correctly positioned.
Furthermore, the present invention relates to a nail machine comprising a tool ring according to the preceding, wherein said nail machine is characterised in comprising a drive device for pulling off a metal wire from a storage, a device for stretching and straightening the wire, a cutter for cutting off desired lengths of elongate bodies of said wire, means for introducing the elongate bodies into the tool ring, a roller for rolling heads onto the elongate body, and means for removing and collecting the elongate bodies provided with heads and to convey said elongate bodies away from the nail machine.